Here you have the neck flap, in colour, with the bead as closure and the broken loop of wool thread that probably served to hold the bead:

If I remember correctly, the bead is made from metal. Here's an even closer closeup, where you can see that it is not a leather thong, but a woolen braid or something similar that holds the bead to the flap.

And finally, in the last picture, you can see the upper left part of the flap, with the braiding running along the edge. The stripes can be seen clearly here.

I took the photos myself; please respect copyright rules when linking to or using them.

You are all very welcome. I know how it feels not to get more and better information on a garment. For the Skjoldehamn finds, at least we can all hope on Dan Halvard Lovlid's thesis for a good new documentation of the garments.And yes, the stripes in the fabric are beautiful. When I saw the pieces, I was absolutely stunned by how well the colours have kept: I was firmly expecting the usual soil-brown of the normal archaeological find.

I think I can see two colours on the cord near the bead. I can almost see the pattern on the cord in the collar photos. No joins visible, so it must be at least a moderately long cord. It taunts me with the feeling I could almost identify the technique (unreliablyand inconclusively I'm afraid) if I saw it closer.

Yes, it is taunting. Unfortunately, that is the most I can make out of the photo I took, no more detail to be had. If I needed to make a try at sewing a copy/reproduction, I would try to identify and then use the braiding pattern that was used in the braid around the flap, since both is roughly the same colour and at the same garment.